The Maryland Democrat, who is not up for reelection until 2016, raised $191,000 in the first three months of this year — many times the $7,737 she collected over the same period last year, according to campaign finance reports filed with the Federal Election Commission. The haul is more than twice what Mikulski raised in all of 2011.

For Mikulski — long the state's most popular politician, with a history of taking at least 60 percent of the vote in elections dating to the 1970s — the windfall underscores her transition from a lawmaker who has typically engaged more on local issues to someone who now chairs a committee that wields tremendous power on the national level.

Mikulski benefited from a number of first-time donations from political action committees, including an association that represents assisted living facilities, one of the nation's largest energy companies and a leading supplier of cement.

"You get money when you have access to money," said David Ferguson, executive director of the Maryland Republican Party.

Mikulski has never been an aggressive fundraiser when not up for re-election, in large part because she's never had to be. Since winning a fifth term in 2010 she raised an average of $38,600 a quarter. In the six years before her last race she raised $5.5 million — most of it in the months leading up to Election Day, according to the Center for Responsive Politics.

The former Baltimore social worker beat Republican Eric Wargotz in 2010 with 62 percent of the vote.

But after being named in December to chair the Appropriations Committee, Mikulski will be expected to take on broader responsibility for her party's prospects in 2014 and 2016.

Though the committee doesn't have the influence it once did — in part because it no longer doles out earmarks — it is still powerful. Mikulski will be expected to contribute more to the Democratic Senatorial Campaign Committee, the campaign arm of Senate Democrats. She also will be called on to get involved in competitive races outside of Maryland.

"I'm a hot ticket," Mikulski quipped in a statement in response to questions about her fundraising, "and I'm getting ready for 2016.

"I'm also working to help elect fellow Democrats to the Senate, especially women."

Although Mikulski has been a safe bet for re-election for years, there was persistent speculation in 2010 that she might retire. And many Maryland Democrats are often mentioned as possible successors, including Reps. Chris Van Hollen and John Delaney — both of whom would be well-funded candidates.

If Mikulski can maintain the increase in fundraising, it would bolster her aura of electoral invincibility.

"Being Appropriations chair isn't what it used to be, but I suspect that being the first woman to chair the [committee] was an added boost to over-the-transom fundraising in the first quarter," said Jennifer Duffy, who tracks Senate races for the nonpartisan Cook Political Report. "Having a flush campaign war chest makes it easier for her to contribute to her colleagues."

Many lawmaker-to-lawmaker contributions are now made from leadership political action committees, accounts set up by senators and House members for that purpose. Such donations are a key way for lawmakers to build personal influence among their colleagues.

A number of corporations gave to Mikulski either for the first time or for the first time in years. North Carolina-based Duke Energy — the country's largest electric power holding company — gave $2,000 in March. Ocean Spray, which has been fighting to keep cranberry juice from being regulated as a sugary drink, contributed $2,500 last month.

Chad Eaton, a communications manger for Duke, stressed that the company's political action committee is run by employees, not management. He said the committee "supports candidates who might be involved in legislation that could impact Duke Energy, our customers and our employees."

Officials at Ocean Spray did not respond to a request for comment. The company's PAC last gave to Mikulski in 2004.

Several high-profile lobbyists also contributed to Mikulski this year. They include Linda Hall Daschle, whose firm represents American Airlines and Lockheed Martin. Daschle is married to Democratic former Senate Majority Leader Tom Daschle.

Kevin F. Kelly, a former Mikulski aide and Appropriations Committee staff member who is now a partner at one of Washington's largest lobbying firms, Van Scoyoc Associates, has given $5,200 to her former boss since the 2012 election.

The increase in donations for new committee chairs is common. A 2011 report by the Citizens for Responsibility and Ethics in Washington found that the top-ranking Democrats and Republicans on House committees received a large bump in campaign cash from the industries their committees oversaw from 1998 to 2010.

First-quarter campaign finance reports for federal lawmakers were due last week.

Rep. Andy Harris, the Baltimore County Republican who was named to the House Appropriations Committee in February, raised $133,138 in the past three months, a roughly 82 percent increase over the same period in 2012.

But Harris has been a prolific fundraiser since winning election to the House in 2010, and the number is not out of line with past reports. The anesthesiologist raised nearly $277,000 in the second quarter of 2011, for instance.

Sen. Richard Shelby of Alabama, Mikulski's opposite number as the top-ranking Republican on the Appropriations Committee, saw a decline in fundraising. He raised $69,691 in the first quarter of 2013 compared with $110,838 over the same period last year. Shelby is also up for re-election in 2016.

Mikulski has had a busy first few months heading the committee. She was immediately confronted with a controversial emergency spending bill to aid victims of Hurricane Sandy. She then faced a March 27 deadline to pass a massive spending bill needed to keep the government running through the end of September.

Despite the drama that has accompanied similar negotiations in the past, Mikulski and Shelby crafted a spending bill that won bipartisan support.

But Mikulski has come under fire for some provisions of that bill, which included measures that she traditionally had opposed. For instance, the legislation, signed by President Barack Obama last month, locked in a pay freeze for federal workers through the end of the year.